1. Field
This disclosure is directed to a polymeric surfactant for high dielectric polymer composites, a method of preparing the same, and a high dielectric polymer composite including the same, and more particularly, to a polymeric surfactant for high dielectric polymer composites, which includes a head portion, having high affinity for a conductive material, and a tail portion, having high affinity for a polymer resin, to a method of preparing the same, and to a high dielectric polymer composite including the same.
2. Description of the Related Art
According to recent industrial trends in electronic products, mobile products are considered to lead technologies and markets. Thus, thorough research and development to decrease the size and weight of mobile products and increase the functionality thereof is being conducted.
In order to realize high-density surface mounting, a substrate is required to have fine via holes and as small a wiring pitch as possible, and to be able to be subjected to a build-up process. Further, IC packages should be miniaturized, pluralities of pins should be used, and passive parts, including condensers and resistors, should be miniaturized and surface mounted. However, with the advancement of the miniaturization of passive devices, the manufacture and mounting thereof become more difficult, and thus the conventional process has many limitations.
To overcome such limitations, there have been proposed techniques for directly forming passive devices, including resistors, inductors, capacitors, etc., on or in a printed circuit board (PCB), instead or mounting them on the PCB. The techniques for embedding passive devices are characterized in that passive devices are inserted outside or inside the substrate using new materials and processes, thereby substituting for the functions of conventional chip resistors and chip capacitors. Accordingly, there is no need to mount chip parts of the passive devices on the printed wiring board, thus realizing high density and high reliability. As the passive devices are embedded in the PCB through such techniques, the surface area of the substrate is decreased, thereby making it possible to decrease the size and weight of products. Further, inductance is reduced, to thereby improve electrical performance, and furthermore, the number of solder joints is decreased, therefore increasing apparatus reliability and reducing the manufacturing cost.
Methods of forcing passive devices on a substrate include, for example, a method of applying a mixture of organic polymer and high dielectric filler, a high loading method using an inorganic filler including barium titanate, and a method of using electron cyclotron resonance chemical vapor deposition (ECR-CVD), which can be used to form a film at low temperatures.
Among the passive devices, the resistor and inductor, which may be formed through a polymer thick film (PTF) process, have some design drawbacks, but entail no great difficulty in terms of materials and manufacturing processes. However, in the case of the capacitor, it cannot be applied to fields requiring a high capacity, because a material having high capacitance and a manufacturing process which enables the application of the material to a low-temperature process (<260° C.) have not been established. Typically, embedded condensers require capacity ranging from 1 pF to 1 μF, depending on the application fields thereof. When a thin film process is used therefor, high capacity may be achieved, but high-temperature annealing should be carried out. Furthermore, the produced ceramic thin film may easily break down when applied to an organic substrate, and the application to FR-4 or flex substrates is also limited, attributable to a high manufacturing process. In contrast, the PTF process may be easily and inexpensively performed and may ensure high applicability to an organic substrate, but results in low dielectric capacity. Hence, attempts to achieve a high dielectric constant with the use of the PTF process have been continuously made.
With the intention of realizing a high dielectric constant, the relate art discloses the use of a polymer composite consisting of a polymer resin and a conductive material. However, the above patent suffers because the conductive material in the polymer composite has a volume % associated with the percolation threshold of the polymer composite. Specifically, when the volume of the conductive material exceeds the percolation threshold of the polymer composite, electrical conduction or percolation between the particles of the conductive material occurs, drastically decreasing the dielectric constant.